This invention relates to rechargeable batteries and more particularly to a simple, inexpensive, charging system whereby a rechargeable battery of the 9 volt physical size and/or electrical characteristics are selectively and alternatively connectible to a charge current source for recharging of the type described in U.S. Pat. No. 4,009,429.
There is an increasing number of consumer products being operated by rechargeable cells such as nickel-cadmium cells. These products require cells with a plurality of physical sizes and electrical characteristics. The variety of cell types in wide use in the consumer market has given rise to the need to provide a unitary charging device to accommodate the various cell types. One such device is described in U.S. Pat. No. 3,579,075 issued on May 18, 1971 and assigned to the assignee of the invention herein. While this device provides a viable approach for charging cells of a variety of types, it has failed to achieve widespread adoption in the consumer market because of its complexity and cost of construction. The system described in the above-identified U.S. Pat. No. 4,009,429 is useful in charging AA, C & D size batteries, but does not accept 9 volt size batteries. The system described in U.S. Pat. No. 4,229,686, readily accepts 9 volt size battery with the use of an adapter.
The ability to charge standard size batteries, e.g. 9 volt snap fit terminal types, raises problems since non-rechargeable batteries may also be attached improperly to the charger with the possibility of damage to the battery or consumer during charging.